In recent years, the organic light emitting diode (OLED) display has been an emerging flat panel display of interest. However, the performance of a traditional OLEDs, especially the low work-function electrode and the organic function layer disposed therein, can be easily deteriorate as oxygen and vapor in the ambient environment enter the OLED display, which may seriously affect the service lifetime of the OLED. To solve this problem, in the prior art, the organic layer of the OLED is isolated from the outside environment by using various materials that achieve a certain sealing performance. Currently, the major sealing method is as follows: filling frit in a packaging area of the upper and lower substrates of an OLED display panel in a nitrogen atmosphere, and then directly irradiating a laser emitted from a laser device onto the frit so that the high temperature generated by the laser will melt the frit and the melted material will tightly bond the upper and lower substrates, thereby achieving package of the OLED device.
However, for the above sealing method, when the frit is irradiated by the laser, it will be heated up rapid, the temperature of which may reach above 800° C. Accordingly, when the frit is cooled down rapidly, stress accumulates, which may lead to cracking of the frit in severe cases and thus result in a package failure.